Checo's championship chances have since taken a major hit, following up a pointless trip to Monaco with a disappointing weekend at the Spanish Grand Prix.
Perez now heads to the Canadian Grand Prix 53 points behind Verstappen after just seven races and desperately needs a victory to keep any faint hopes of a title battle alive.
Prost's Perez advice
"A driver's game is always to try and tip the balance in his favour, whether it's the set-up of the car or the contribution of the team. And that's where Perez is wrong," explained Prost in his column for L'Equipe.
"He needs to make Max Verstappen doubt him and change Red Bull's mind about him. As we know, Perez is tackling an almost impossible mission. And in order to achieve it, he must above all not shout so loudly about his desire to beat Max."
Prost also had some choice words for Sergio Perez's father, who is often seen close to Checo on race weekends.
"His entourage isn't helping him either. When I read a month ago that his father told journalists that his fight with Max was similar to the one I had with Ayrton (Senna), it's pointless and counterproductive."